feat: add sse-counter example (#110)

Author: sergiodxa

sse-counter/.eslintrc.js

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+/** @type {import('eslint').Linter.Config} */
+module.exports = {
+  extends: ["@remix-run/eslint-config", "@remix-run/eslint-config/node"],
+};

sse-counter/.gitignore

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+node_modules
+
+/.cache
+/build
+/public/build
+.env

sse-counter/README.md

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+# Server-Sent Events - Counter
+
+This example demonstrates how to use Server-Sent Events to create a simple counter that updates in real-time.
+
+## Preview
+
+Open this example on [CodeSandbox](https://codesandbox.com):
+
+[![Open in CodeSandbox](https://codesandbox.io/static/img/play-codesandbox.svg)](https://codesandbox.io/s/github/remix-run/examples/tree/main/sse-counter)
+
+## Example
+
+The example uses the `eventStream` response helper from Remix Utils to implement a SSE endpoint.
+
+In that endpoint the server starts an interval that emits a new message every second with the current time formatted in English.
+
+Client-side, the `useEventSource` hook from Remix Utils is used to subscribe to the SSE endpoint and display the new date.
+
+## Related Links
+
+- [Server-Sent Events](https://developer.mozilla.org/en-US/docs/Web/API/Server-sent_events)
+- [Remix Utils](https://github.com/sergiodxa/remix-utils#server-sent-events)
+- [Event Emitter](https://nodejs.org/api/events.html#events_class_eventemitter)

sse-counter/app/entry.client.tsx

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+import { RemixBrowser } from "@remix-run/react";
+import { startTransition, StrictMode } from "react";
+import { hydrateRoot } from "react-dom/client";
+
+const hydrate = () =>
+  startTransition(() => {
+    hydrateRoot(
+      document,
+      <StrictMode>
+        <RemixBrowser />
+      </StrictMode>
+    );
+  });
+
+if (window.requestIdleCallback) {
+  window.requestIdleCallback(hydrate);
+} else {
+  // Safari doesn't support requestIdleCallback
+  // https://caniuse.com/requestidlecallback
+  window.setTimeout(hydrate, 1);
+}

sse-counter/app/entry.server.tsx

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+import { PassThrough } from "stream";
+
+import type { EntryContext } from "@remix-run/node";
+import { Response } from "@remix-run/node";
+import { RemixServer } from "@remix-run/react";
+import isbot from "isbot";
+import { renderToPipeableStream } from "react-dom/server";
+
+const ABORT_DELAY = 5000;
+
+const handleRequest = (
+  request: Request,
+  responseStatusCode: number,
+  responseHeaders: Headers,
+  remixContext: EntryContext
+) =>
+  isbot(request.headers.get("user-agent"))
+    ? handleBotRequest(
+        request,
+        responseStatusCode,
+        responseHeaders,
+        remixContext
+      )
+    : handleBrowserRequest(
+        request,
+        responseStatusCode,
+        responseHeaders,
+        remixContext
+      );
+export default handleRequest;
+
+const handleBotRequest = (
+  request: Request,
+  responseStatusCode: number,
+  responseHeaders: Headers,
+  remixContext: EntryContext
+) =>
+  new Promise((resolve, reject) => {
+    let didError = false;
+
+    const { pipe, abort } = renderToPipeableStream(
+      <RemixServer context={remixContext} url={request.url} />,
+      {
+        onAllReady: () => {
+          const body = new PassThrough();
+
+          responseHeaders.set("Content-Type", "text/html");
+
+          resolve(
+            new Response(body, {
+              headers: responseHeaders,
+              status: didError ? 500 : responseStatusCode,
+            })
+          );
+
+          pipe(body);
+        },
+        onShellError: (error: unknown) => {
+          reject(error);
+        },
+        onError: (error: unknown) => {
+          didError = true;
+
+          console.error(error);
+        },
+      }
+    );
+
+    setTimeout(abort, ABORT_DELAY);
+  });
+
+const handleBrowserRequest = (
+  request: Request,
+  responseStatusCode: number,
+  responseHeaders: Headers,
+  remixContext: EntryContext
+) =>
+  new Promise((resolve, reject) => {
+    let didError = false;
+
+    const { pipe, abort } = renderToPipeableStream(
+      <RemixServer context={remixContext} url={request.url} />,
+      {
+        onShellReady: () => {
+          const body = new PassThrough();
+
+          responseHeaders.set("Content-Type", "text/html");
+
+          resolve(
+            new Response(body, {
+              headers: responseHeaders,
+              status: didError ? 500 : responseStatusCode,
+            })
+          );
+
+          pipe(body);
+        },
+        onShellError: (error: unknown) => {
+          reject(error);
+        },
+        onError: (error: unknown) => {
+          didError = true;
+
+          console.error(error);
+        },
+      }
+    );
+
+    setTimeout(abort, ABORT_DELAY);
+  });

sse-counter/app/root.tsx

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+import type { MetaFunction } from "@remix-run/node";
+import { json } from "@remix-run/node";
+import {
+  Links,
+  LiveReload,
+  Meta,
+  Outlet,
+  Scripts,
+  ScrollRestoration,
+  useLoaderData,
+} from "@remix-run/react";
+import { useEventSource } from "remix-utils";
+
+export const meta: MetaFunction = () => ({
+  charset: "utf-8",
+  title: "New Remix App",
+  viewport: "width=device-width,initial-scale=1",
+});
+
+export function loader() {
+  return json({
+    initialCount: new Date().toLocaleTimeString("en", {
+      hour: "2-digit",
+      minute: "2-digit",
+      second: "2-digit",
+    }),
+  });
+}
+
+export default function App() {
+  const { initialCount } = useLoaderData<typeof loader>();
+  const count = useEventSource("/sse/counter") ?? initialCount;
+  return (
+    <html lang="en">
+      <head>
+        <Meta />
+        <Links />
+      </head>
+      <body>
+        <h1>
+          The server time is <time>{count}</time>
+        </h1>
+        <Outlet />
+        <ScrollRestoration />
+        <Scripts />
+        <LiveReload />
+      </body>
+    </html>
+  );
+}

sse-counter/app/routes/sse.counter.ts

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+import type { LoaderArgs } from "@remix-run/node";
+import { eventStream } from "remix-utils";
+
+export function loader({ request }: LoaderArgs) {
+  return eventStream(request.signal, function setup(send) {
+    const interval = setInterval(() => {
+      send({
+        data: new Date().toLocaleTimeString("en", {
+          hour: "2-digit",
+          minute: "2-digit",
+          second: "2-digit",
+        }),
+      });
+    }, 1000);
+
+    return function cleanup() {
+      clearInterval(interval);
+    };
+  });
+}

sse-counter/package.json

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+{
+  "private": true,
+  "sideEffects": false,
+  "scripts": {
+    "build": "remix build",
+    "dev": "remix dev",
+    "start": "remix-serve build"
+  },
+  "dependencies": {
+    "@remix-run/node": "*",
+    "@remix-run/react": "*",
+    "@remix-run/serve": "*",
+    "isbot": "^3.6.5",
+    "react": "^18.2.0",
+    "react-dom": "^18.2.0",
+    "remix-utils": "^5.1.0"
+  },
+  "devDependencies": {
+    "@remix-run/dev": "*",
+    "@remix-run/eslint-config": "*",
+    "@types/react": "^18.0.25",
+    "@types/react-dom": "^18.0.8",
+    "eslint": "^8.27.0",
+    "typescript": "^4.8.4"
+  },
+  "engines": {
+    "node": ">=14"
+  }
+}

sse-counter/public/favicon.ico

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+/** @type {import('@remix-run/dev').AppConfig} */
+module.exports = {
+  ignoredRouteFiles: ["**/.*"],
+  // appDirectory: "app",
+  // assetsBuildDirectory: "public/build",
+  // serverBuildPath: "build/index.js",
+  // publicPath: "/build/",
+};